/*
 * @(#)$Id$
 *
 * Copyright 2006-2008 Makoto YUI
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * Contributors:
 *     Makoto YUI - initial implementation
 */
package gridool.locking;

import gridool.util.collections.SoftHashMap;

import java.util.Map;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;


/**
 * 
 * <DIV lang="en"></DIV>
 * <DIV lang="ja"></DIV>
 * 
 * @author Makoto YUI (yuin405@gmail.com)
 */
public final class SoftValueLockManager implements LockManager {

    private final Map<Object, ReadWriteLock> lockPool;

    public SoftValueLockManager() {
        this.lockPool = new SoftHashMap<Object, ReadWriteLock>(32);
    }

    public synchronized ReadWriteLock obtainLock(final Object resource) {
        ReadWriteLock lock = lockPool.get(resource);
        if(lock == null) {
            lock = new ReentrantReadWriteLock();
            lockPool.put(resource, lock);
        }
        return lock;
    }

}
